This invention relates to a fuel assembly, and more particularly to a fuel assembly having a fuel spacer consisting of a large number of circular members.
As a fuel assembly for use in a boiling water reactor, a fuel assembly is known which has a fuel spacer consisting of a large number of circular sleeves. This fuel assembly is disclosed in Japanese patent Laid-Open No. 65287/1984 (basic application: U.S. Patent application Ser. No. 410124 filed on Aug. 20, 1982), and is illustrated in FIG. 2 of the Japanese reference.
The fuel spacer is produced by arranging a large number of circular sleeves, into which fuel rods are inserted, in grid form and coupling adjacent circular sleeves with one another by welding. A water rod is also inserted into the circular sleeve in the same way as the, fuel rods. The support of the fuel spacer by the water rod is shown in FIGS. 8A-8C and 9A-9B of the Japanese reference.
Development of a fuel assembly, which includes a water rod having an increased outer diameter, has also been made. An example of such fuel assemblies is shown in FIG. 1 of Japanese patent Laid-Open No. 65792/1984. The outer diameter of the water rod in this fuel assembly is about twice the outer diameter of the fuel rod.